1. Field of the Invention
The present invention relates to a camera system having an accessory, which can be attached to a camera body, and has an electrical contact connected to the camera body when it is attached to the camera body, so that data associated with photographing data, stored in the accessory, can be transferred to the camera body.
2. Related Background Art
As camera systems described in the prior art and related the present invention, two typical conventional camera systems are known. In one camera system, data stored in a lens is sent back to a camera body in response to address data serially transferred from the camera body. In the other camera system, data stored in a lens is sent back to a camera body in response to start pulses generated from the camera body. The following problems in such systems are posed, taking into consideration cameras having various functions. More specifically, in the first system, each time one data in the lens is to be read, address data must be designated. If a large volume of data must be read, a time interval required for designating address data is undesirably long. In the second system, when all the data in the lens is to be transferred to the camera body, if the camera body comprises a small-capacity RAM (Random Access Memory), the data cannot be stored therein. In addition, data volume is increased, a time required for data transfer is prolonged, and a problem may occur in accordance with a processing content.